Common respiratory viruses are typically active in the fall and winter and relatively silent in the summer. the 2003 severe acute respiratory syndrome (SARS) outbreak also receded as the weather turned warmer.
As the Northern Hemisphere, which is home to about 90% of the planet's population, enters summer, will the spread of new coronaviruses, reported as early as winter 2019, be contained by warmer temperatures?
Experts say the idea of relying on warming to control outbreaks lacks scientific evidence to support it, but certain properties of new coronaviruses, as well as people's immune systems and behavioral patterns, may change with the seasons and temperatures, thus having some impact on outbreak development.
--New coronaviruses can be transmitted in all regions
The global outbreak and continued spread of the outbreak have demonstrated the ability of the virus to spread in all climatic conditions. The World Health Organization (WHO) has also stated that the evidence to date shows that NCA virus can spread in all regions, including hot and humid climates. Regardless of climatic conditions, people must take protective measures if they live in or travel to areas where outbreaks have been reported.
Tom Kotzinbos, an associate professor at Monash University in Australia, recently told the media that the New Coronavirus outbreak is spreading quickly around the world, both in the northern and southern hemispheres. This suggests that either the spread of the new crown virus does not depend on temperature, or this dependence does not matter.
-- Can high temperatures "kill" the virus? Conflicting findings
So is the spread of the new coronavirus actually affected by temperature? There is a lack of conclusive data on this issue globally, and the few published studies that have tried to find a link have even reached conflicting conclusions.
A team from the School of Public Health at the University of Hong Kong Medical School in China published an article in the British journal The Lancet Microbiology on the 2nd, saying they tested the stability of the new coronavirus at different temperatures and found that the lower the temperature, the more stable the new coronavirus. At 37 degrees Celsius, the virus remained stable for only 3 to 4 hours, and the infectiousness dropped to 0.1% after 1 day.
However, a study published in the online edition of the European Respiratory Journal by a team from the School of Public Health at Fudan University in China on 8 August said that climate factors such as temperature and ultraviolet radiation did not have a significant impact on the spread of the new coronavirus in terms of transmission in urban China. This outbreak pattern is similar to that of Middle East Respiratory Syndrome (MERS), where the number of MERS cases continues to grow when temperatures exceed 45 degrees Celsius.
Professor Zhu Yifang, associate dean of the UCLA School of Public Health, said in a recent interview with Xinhua that the study was constrained by experimental data, and the scope of the temperature and epidemic analysis was narrow, and it is questionable whether the findings can be extended to the world.
--Watch out for "overlap" of new crown epidemic and flu season
According to Curt Simbers of Monash University in Australia, although there is a lack of understanding of the impact of temperature on the development of the epidemic, the impact must exist, which is related to the biological characteristics of the virus, people's immune status, environmental and behavioral conditions.
He said, Australia is about to enter the autumn and winter season, if the new crown epidemic period and the flu season "overlap", not only will cause great pressure on the health care system, but also to bring a different challenge to the individual immune system. However, studies have also shown that recent recovery from viral infections may strengthen the immune system and help it attack other viruses.
--Seasonal factors outside of temperature exert influence on outbreaks
Michael Skinner, an academic in the field of virology at Imperial College in the United Kingdom, told Xinhua that it is conceivable that in most countries that have adopted control measures, new coronaviruses are transmitted mainly within households and between households. In contrast, inter-household transmission occurs over longer distances, such as through aerosols, and such transmission is likely to be influenced by climatic factors, but it is difficult to calculate how large that influence is.
Chris Burrell, professor emeritus of virology at the University of Adelaide in Australia, believes that a major reason why viruses are more likely to spread in winter is that "people often gather together. For example, preschoolers spend their summers in the sun and don't have much physical contact with each other. In the winter, they stay indoors and breathe the same air. But any effect that temperature has on the new coronavirus will not be as important as limiting its spread through isolation measures.
Zhu Yifang said she did not rule out the possibility that the epidemic could ease as temperatures rise in the Northern Hemisphere, and it is still unknown whether the epidemic will return in the second half of the year as the Northern Hemisphere enters the fall and winter, or whether it will recur periodically with temperatures.
